The field of invention relates generally to semiconductor device processing. More particularly, the present invention is directed to a method of compensating for a volumetric shrinkage of a material disposed upon a substrate to form a substantially planar structure therefrom.
Micro-fabrication involves the fabrication of very small structures, e.g., having features on the order of micro-meters or smaller. One area in which micro-fabrication has had a sizeable impact is in the processing of integrated circuits. As the semiconductor processing industry continues to strive for larger production yields while increasing the circuits per unit area formed on a substrate, micro-fabrication becomes increasingly important. Micro-fabrication provides greater process control while allowing increased reduction of the minimum feature dimension of the structures formed. Other areas of development in which micro-fabrication has been employed include biotechnology, optical technology, mechanical systems and the like.
As the minimum features size of structures formed on substrates is reduced, the need to form a substrate having a substantially planar surface is increased. A method of planarizing a substrate is disclosed in U.S. Patent Application Publication 2003/0184917 to Chang et al. Chang et al. describes a method of reducing step heights in the planarization of thin film carriers in an encapsulation system by utilizing an adhesive tape having a thinner adhesive thickness and a stiffer tape for the film sealing the encapsulant on the carrier to result in a low step height surface transition between the carrier and the cured encapsulant. Also, the composition of the encapsulant may be altered to reduce the shrinkage thereof during curing. A first approach to alter the composition of the encapsulant is to include absorbents in the formulation of the encapsulant to absorb the irradiation and reduce the curing effect. A second approach to alter the compostion of the encapsulant is to add a gas-emitting additive into the encapsulant, which will be converted into gaseous products upon irradiation.
Another method of planarizing a substrate is disclosed in U.S. Pat. No. 6,218,316 to Marsh. Marsh describes a method of planarizing a substrate having a planarization material disposed thereon and bringing a substantially flat surface into contact therewith. The planarization material is exposed to radiation at a first wavelength of light to cure the planarization material and is exposed to radiation at a second wavelength of light to cause changes to the planarization material that facilitate separation of the substantially flat surface from the planarization material.
It is desired, therefore, to provide an improved method of planarizing a substrate.